Questions tagged [iterator]
An iterator is an object-oriented programming pattern which for the most part functions similarly to a pointer to an object inside a collection with the added ability to traverse through the collection in a defined manner, agnostic of the actual implementation or even object addresses in physical memory. Iterators may be further limited in particular traversal directions.
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Compare length of iterator with as few `next` calls as possible. How can I deduplicate this code?
I'm writing a few simple functions that compare the length of an iterator to an integer, returning as early as possible. Right now I have:
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1answer
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c# QuadTree yielding properly [closed]
I have implemented a QuadTree of my own, and I'm afraid I didn't use yield properly when I query my tree, my fear is that I create O(HN) iterators.
Could you direct me how to better improve the ...
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Iterating through map keys in C++ 17 [migrated]
I am looking for a way to iterate through the keys of a map in C++ 17. The way that I have in mind right now is based on the answer of this question, the way is presented below.
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Populate a list with combinations of one- and two- object functions
I have a nested set of for loops which achieves the desired outcome, but I don't know if it is the most efficient / pythonic way of populating this list.
I would ...
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Manipulating list values in python
I wrote a function that I use to preprocess pandas dataframes before running them through a machine learning model. The function works perfectly, however I don't think it's the most pythonic way to ...
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1answer
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Summation Over Lines in a File (Advent of Code 2018 Day 1)
Preface: I am learning Rust through the Advent of Code
The task is to read lines from a file, parse each as an integer, then provide a summation of all the numbers. My solution looks like this:
<...
3
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1answer
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Iterate through Expression Tree
I'm trying to build an iterator (enumerator) that can select specific elements in an Expression tree by traversing the tree and deferring further iteration until ...
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2answers
210 views
C++17 zip iterator compatible with std::sort
Here are ~100 lines of code implementing three classes (ZipRef, ZipIter, Zip) which should ...
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2answers
692 views
Iterator for traversing a tree [v2]
this is an update of the implementation after I followed the feedback from Iterator for traversing a tree. After that I did changed quite a bit on the design and decided to ask for another round of ...
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1answer
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1answer
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Bidirectional numeric (floating point) sequence iterator
I wanted a neat iterator that will always give me neat sequence of step spaced numbers. This is what I came up with, but I am a bit skeptical that I covered all ...
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0answers
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Combining two nested for loops into one [closed]
Description
What this does is it takes a randomly generated 64x64 stack and checks
for overlap within the 64x64 array. Here is an example:
https://imgur.com/a/kkPRzhn. Each color is its own ...
2
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1answer
59 views
A simple priority queue in Java via linked list sorted by priority keys
Now I have this very simple priority queue. add and changePriority both run in \$\mathcal{O}(n)\$ and ...
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1answer
60 views
A GapHelper static class to create unique (non-existing) size restricted names
I am working with a 3th party library which has following interface defined for a processing task:
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1answer
212 views
Map unique raw words to a list of code words
Problem
Write a function that replaces the words in raw with the words in code_words such that the first occurrence of each ...
3
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1answer
68 views
Aggregation on list forEach and maps improvals
I am using a function in a SpringBoot @RestController, with Lombok
This function is an intermediate result that permit me to do an aggregation between two classes.
This 2 classes are:
...
1
vote
1answer
86 views
c++ python like range function to use in for loops
It's a simple range function that works like python range and it is only a syntactic sugar for the usual for loop
if we want to operate on numbers in the range from 1 to 10 (1 ... 9) we use this code ...
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3answers
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LINQ Extension methods MinBy and MaxBy
LINQ Extension
I present a LINQ method ArgBy that returns the item of a sequence that corresponds to the predicate specified. Two additional methods ...
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2answers
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Doubly-linked-list implementation in C++
I am fairly new to C++ and have been trying to make a doubly-linked-list class that imitates std::list (though not all of it). I'd appreciate if someone can look at my code and let me know if I have ...
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2answers
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A basic trivia app
The app grabs 10 questions from an API, displays them one by one with 4 multiple choice answers. These answers are clickable buttons that alert to whether the answer is correct or not. Finally the ...
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votes
2answers
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Python-style Generator in Java
I have implemented Python-style generators within Java. I might be reinventing the wheel here, but I feel that the ability to define a Generator with an anonymous class is the most flexible approach. ...
2
votes
1answer
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C++ singly linked list with iterator
I have written a simple singly linked list in C++. I have previously had a data structure in an interview criticised for being too C-like (no iterators and using new/delete) instead of smart pointers. ...
2
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1answer
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Add method to Ruby's Enumerable module that produces every nth element
The task is to enhance the Enumerable module with a method nth().
The method shall create a new list, which contains every nth-...
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0answers
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General algorithm to calculate sums of all subsets of a given sequence of numbers
Background
A recent question Print sums of all subsets made its way to the Hot Network Questions list. The problem is simple:
Print sums of all subsets of a given set
Given an array of ...
5
votes
2answers
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Filename sequencer with outdated C++
My path to learning C++ has been a rough one. Currently, I'm writing a project and my knowledge is very outdated. While I can write code that accomplishes the tasks required, I'd like to improve and ...
2
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2answers
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Implementation of enumerate
I'm trying to implement the enumerate built-in using iterators. So far it works but for unordered objects, such as sets or dictionaries, I'm not sure if this implementation is considered valid, ...
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3answers
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SkipLast of an IEnumerable<T> - Linq Extension
As my answer to this question, I came up with this solution:
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4
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1answer
50 views
Using best practice with complex iteration
I'm new to Rust so I'm still learning how to use best practice in complex examples.
Below is some code I've used in one of my programs, a simple implementation of a standard neural network.
Here is ...
4
votes
1answer
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Email Generator
I've made a email generator, that uses a HTML template and replaces keywords in the template with information taken from a database. I'm looking to see if there is a way to improve the coding.
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1answer
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C function to fully consume a Python iterator
I was reading into the proper way to consume an iterator on this question as well as here and I notices there is no actual proper function for this that clearly explains itself.
Using:
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1answer
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Rendering JSON arrays of unequal length as a table
I have a website where my users can create "table-like" layout dynamically. So imagine that my users can upload a text document, and then append columns to the document, and the output will then be ...
4
votes
1answer
79 views
Iterable hashtable implementation in C
I'm just finished my version of iterable hashtable. I want to review code in general (code style, data structures, remarks about the algorithms) and I have some questions:
I don't know how to ...
1
vote
1answer
60 views
Replace values in R data frame according to values in other data frame
I would like to change row names values from a first data frame if these rows names are present in another data frame, and change it to a corresponding value (defined in the second data frame). I ...
3
votes
1answer
94 views
Most efficient way to loop through files using VBA Excel
I have a procedure for looping through all files in folders and subfolders starting at a folder which the user can select. The user can select both the source and target folder. I'm using Excel VBA ...
3
votes
0answers
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Rust Iterator that correlates a slice with itself
In my effort to learn Rust I've tried implementing an Iterator that splits up a buffer in two halves, and correlates both halves by sliding them over each other with different positions (lags). You ...
2
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2answers
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1
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1answer
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Sequence for Pre-order traversal of Binary Trees
I wanted to make a Sequence that can do a pre-order traversal of Binary Tree. Doing so provides automatically unlocks wonderfully useful methods, like ...
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2answers
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Simple linked list with two iterators
As part of the practice, I created minimalist linked list named SimpleList which can be iterated in two different ways: one element after another or by every second ...
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4answers
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Count all vowels in string
For a homework assignemnt, I was asked to complete this CodeStepByStep problem. It's coded correctly and gave me a right answer. I'm just wondering if there's an easier way to solve this problem ...
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2answers
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Combining arbitrary number of lists inside json
I have some JSON where each key stores an array, and I need to combine all those arrays into a single array. My current solution doesn't seem the most friendly to review, but without ...
2
votes
1answer
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Speed up fast poisson disk sampling generator in Python
I wrote a generator class which implements Fast Poisson Disk Sampling algorithm in Python. I did some optimizations like, x ** 2 -> x * x, using unpacking ...
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3answers
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Linked list implementation C++
I hope this is the right way of doing things: I've previously posted a request for a code review and gotten feedback. Now I have new improved code that I would like a code review on again. Old: C++ ...
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2answers
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C++ linked list iterator implementation
I'm a first year computer engineering student and would appreciate feedback on some code.
I've created a linked-list with an iterator to be able to range for loops like: ...
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0answers
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Generating integer partitions
I've tried to implement integer partition algorithm as described in blogpost below (author implemented it in Python):
Generating integer partitions
I'm still trying to learn best practices in ...
3
votes
1answer
73 views
Optimizing quicksort
I created simple quicksort algorithm using iterators. I'm happy with implementation but not with its speed. Profiler tells me that the slowest operation here is ...
2
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2answers
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JS to create Table data dynamically
The following codes generate table row dynamically. I wonder if there are better ways of generating the same data. Also instead of manually coding the heading and the table itself, is it possible to ...
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0answers
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itertools.produce reduced and filtered
I need to generate list of all allowable test combination values of of actor, action and ...
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3answers
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Decoding assembly instructions in a Game Boy disassembler
I am coding a game boy disassembler in C++. The program (simplified here) converts a vector of byte into an assembly instruction and print it.
To do so, it iterates through the vector of bytes (char)...
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votes
1answer
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Short analogue of Riffle[] accepting two blocks
I have an array of some elements that I need to loop through (i.e. execute some block A on each element) but between them I have also to "clean up" (block ...
